I brought my 1995 ls blazer to a mechanic when the check engine light came on. He told me the number 4 injector is intermitently firing and the ignition module is putting out 37,000 volts when it should be putting out 90,000. Here are the fixes he suggested to me:

Injectors - He claims he can clean it with sea foam. I thought it would be better to change it with a new one, but he said he is 150 percent sure he can clean it with sea foam doing a high pressure cleaning. To me it would make more sense to change it along with the others to make sure i don't have a problem again for a while.

Ignition module - he wants to change this which i agree upon. I am not ignorant when it comes to mechanics but i am having a hard time understanding how a 12 volt systel can produce 90,000 volts as he stated. Is this possible or should he have used another phrase while having the numbers right?


Thanks ahead of time for the feedback. This truck is in very good shape so i don't mind putting money into it i am just trying to make sure this mechanic knows what he is talking about.

 

He also stated that i have the early injection system which is the good one. Originally i was told by another mechanic that it was the spider assembly

 

All 1995 S-series Blazers have the CPI 4.3L engine. You do not have a single injector for cylinder 4, rather one large injector feeding six individual pressure actuated poppet nozzles. So having the injector go bad would affect all cylinders. The poppet nozzles can be problematic and while it is possible to clean them, seafoam would not be the first choice I would make. A few stiff mixes of Chevron Techron Fuel System Treatment Plus would let you know if it is something that can be fixed with a bottle or something that needs further intervention.

As far as the ignition module, they can be tested at almost any autoparts store. Have it tested repeatedly to show any signs of heat related issues.

 

If the treatment bottle does not work and you are looking at replacing the spider unit (be prepared on cost BTW, the labor is a killer) make sure that the upper and lower intake manifolds get changed as well. They will need to at least have the upper off to do the injector, and since you are there get the second one done to I would at least suggest.

You can go ahead and replace the one nozzle that went bad, in my situation I had two that were bad + the fuel pressure regulator and I decided to just replace the whole unit. Rather do that now then have to replace another nozzle later.

That one cyl plug should be replaced as well, it is prob saturated with gunk/fuel. Have you done a full tune up on it? I would replace the cap and rotor, plugs, wire, etc before limiting that the cyl is going bad.